Optical recording medium

Abstract

An optical recording medium is disclosed, in which an optical recording layer and a reflective layer are formed on a transparent substrate. The recording layer contains a first compound having absorption or a recording laser light having a predetermined wavelength, and a second compound having substantially no absorption for a laser light having the predetermined wavelength and decomposable upon heat generation by the laser light in the optical recording layer.

We claim as our invention: 
     
       1. An optical recording medium comprising a transparent substrate, an optical recording layer formed on said transparent substrate, a reflective layer formed on said optical recording layer, said optical recording layer containing a first compound having absorption for a recording laser light having a predetermined wavelength, and a second compound having substantially no absorption for a laser light having said predetermined wavelength and decomposable upon heat generation by said laser light in said optical recording layer, said optical recording layer has a complex refractive index of n*=n+ik, wherein 1.5≦n≦3.2, and 0≦k≦0.2, said first compound has a complex refractive index of n*=n ik wherein 1.5≦n≦3.2 and 0.3≦k, and said second compound has a complex refractive index of n*=n+ik, wherein 1.5≦n≦3.2, and k≦0.05 wherein n* is a complex refractive index and "n" is the real part, "i" is an imaginary part and "k" is an extinction coefficient. 
     
     
       2. An optical recording medium according to claim 1, said first compound has a complex refractive index of n*=n+ik, wherein 1.5≦n≦3.2, and 0.3≦k≦2.0. 
     
     
       3. An optical recording medium according to claim 1, said second compound has a complex refractive index of n*=n+ik, wherein 1.5≦n≦3.2, and k≦0.019. 
     
     
       4. An optical recording medium according to claim 1, said optical recording layer has a thickness of about said predetermined wavelength divided by 2n, wherein n is an integer. 
     
     
       5. An optical recording medium according to claim 1, said reflective layer has a thickness between 300 and 2000 Å. 
     
     
       6. An optical recording medium according to claim 1, said first compound is selected from the group of cyanine base dyes, metal complex base dyes, phthalocyanine dyes and naphthalocyanine dyes. 
     
     
       7. An optical recording medium comprising a transparent substrate, an optical recording layer formed on said transparent substrate, a reflective layer formed on said optical recording layer, said optical recording layer containing a first compound having absorption for a recording laser light having a predetermined wavelength, and a second compound having substantially no absorption for a laser light having said predetermined wavelength and decomposable upon heat generation by said laser light in said optical recording layer, said first compound is selected from the group of cyanine base dyes, metal complex base dyes, phthalocyanine dyes and naphthalocyanine dyes, and said first compound is substituted aminophthaloscyanines, represented by the following formula, ##STR15## (in the above formula, K 1  to K 4  stand for a hydrogen atom, an amino group, a substituted amino group or the like, with at least one of K 1  to K 4  being however a substituted amino group. If two or more of K 1  to K 4  are substituted amino groups, these substituted amino groups may be the same as or different from each other.) 
     
     
       8. An optical recording medium according to claim 6, said second compound is selected from the group of cyanine dyes, coumarin dyes, alantoin base dyes, azo base dyes, triphenylmethane base dyes, acridine base dyes, oxazine base dyes, bisazo base dyes and xanthene base dyes. 
     
     
       9. An optical recording medium according to claim 7, wherein said second compound is selected from the group of cyanine dyes, coumarin dyes, alantoin base dyes, azo base dyes, triphenylmethane base dyes, acridine base dyes, oxazine base dyes, bisazo base dyes and xanthene base dyes.